Airbag device for saddle-type vehicle

Abstract

An airbag device for a saddle-type vehicle which can restrict an airbag from being separated until the airbag is deployed so that the airbag can be separated in a deployed state. The airbag device includes an inflator and an airbag, and has a first restriction portion that restricts separation between the inflator and the airbag. The first restriction portion has an elastic member positioned inside the inflator. When the inflator releases a gas having a first gas release pressure, the elastic member is increased in diameter due to the gas pressure, and the inflator and the elastic member enter a locked state and restrict separation of the airbag. When the inflator releases a gas having a second gas release pressure, the elastic member diameter is decreased to be smaller than the diameter in the locked state, the locked state is canceled, and separation of the airbag is unrestricted.

The invention claimed is: 
     
       1. An airbag device for a saddle vehicle which includes an inflator having an opening, and an airbag that is connected to an inside of the inflator through the opening and is deployed with a gas released by the inflator, the airbag device comprising:
 a first restriction portion that restricts separation between the inflator and the airbag when the airbag is deployed, wherein 
 the first restriction portion has an elastic member positioned inside the inflator, 
 when the inflator releases a gas having a predetermined first gas release pressure, the elastic member is increased in diameter due to the gas pressure of the inflator, and the inflator and the elastic member enter a locked state, so that the first restriction portion restricts separation of the airbag, and 
 when the inflator releases a gas having a predetermined second gas release pressure lower than the first gas release pressure after the gas having the first gas release pressure is released, the elastic member is decreased to have a diameter smaller than the diameter in the locked state, and the locked state is canceled, so that the first restriction portion releases restriction on separation of the airbag. 
 
     
     
       2. The airbag device of a saddle vehicle according to  claim 1 , wherein
 the inflator includes a gas ejection unit that extends in an axial direction and that has a hollow gas ejection passage inside the gas ejection unit, and 
 a plurality of gas ejection ports communicating with the gas ejection passage are formed in an outer circumferential surface of the gas ejection unit. 
 
     
     
       3. The airbag device of a saddle vehicle according to  claim 2 , wherein
 the elastic member is disposed to have an overlapping portion which at least partially overlaps the gas ejection port in the axial direction. 
 
     
     
       4. The airbag device of a saddle vehicle according to  claim 2 , wherein
 the gas ejection unit is positioned inside the inflator in the axial direction. 
 
     
     
       5. The airbag device of a saddle vehicle according to  claim 2 , wherein
 a check valve is attached to the airbag. 
 
     
     
       6. The airbag device of a saddle vehicle according to  claim 2 , wherein
 the inflator has a circumferential portion provided around the gas ejection unit, 
 a part of the airbag is positioned between the circumferential portion and the elastic member in a radial direction, and 
 the elastic member is increased in diameter, and the airbag is sandwiched between the circumferential portion and the elastic member, so that separation of the airbag is restricted. 
 
     
     
       7. The airbag device of a saddle vehicle according to  claim 2 , comprising:
 a second restriction portion that restricts the airbag airbag from being separated from the inflator in a state before gas release, wherein 
 the second restriction portion is unrestricted by heat generated at the time of gas release from the inflator. 
 
     
     
       8. The airbag device of a saddle vehicle according to  claim 7 , wherein
 the inflator has a circumferential portion provided around the gas ejection unit, 
 the second restriction portion is provided in the airbag and is positioned upstream of an inner end portion in the inflator, the inner end portion being an end portion of the elastic member positioned upstream in the inflator, and 
 a diameter is larger than a gap between the circumferential portion and the elastic member in the radial direction. 
 
     
     
       9. The airbag device of a saddle vehicle according to  claim 7 , wherein
 the second restriction portion is melted by heat at the time of gas release from the inflator. 
 
     
     
       10. The airbag device of a saddle vehicle according to  claim 7 , wherein
 the second restriction portion is an anchoring portion that anchors the airbag to the elastic member or the inflator, 
 the anchoring portion is positioned downstream of an inner end portion in the inflator, the inner end portion being an end portion of the elastic member positioned upstream in the inflator, and 
 the anchoring portion is melted by heat at the time of gas release from the inflator. 
 
     
     
       11. The airbag device of a saddle vehicle according to  claim 2 , wherein
 the elastic member is integrally attached to the airbag, 
 the inflator has an opening portion, 
 the opening portion has a locking portion, 
 the elastic member is positioned further inside the inflator in the axial direction than the locking portion, 
 the locking portion has an overlapping portion that at least partially overlaps, in the radial direction, the elastic member increased to have the large diameter by the gas having the first gas release pressure, and 
 the overlapping portion is formed in a shape that does not overlap, in the radial direction, the elastic member decreased to have a small diameter by the gas having the second gas release pressure. 
 
     
     
       12. The airbag device of a saddle vehicle according to  claim 11 , wherein
 at least a part of the elastic member is press-fitted into the gas ejection unit.